Human colon cancer is one of the most common malignancies in this country. The proposed investigation seeks to chemically and immunologically characterize cell surface antigens distinctive of colonic neoplasia signals and receptor sites determining organoid differentiation. The applicants have previously initiated, established and characterized human colon cancer cell lines in continuous tissue culture. Chemical studies comparing the surface membrane profiles as well as solubilized components of neoplastic versus normal colonic tissue cells revealed multiple differences. Immunological tools are being used to determine which of the altered proteins is distinctive of the neoplastic state and might be harnessed as immunodiagnostic and/or immunotherapeutic tools. Monoclonal anti-colonic carcinoma antibodies prouced by hybridization of myeloma (P3 x 63AG8) with lymphoid cells derived from murine hosts pre-immunized with whole cell or soluble extracts of a variety of colonic neoplastic cell lines will be tested for a) immunological reactivity detected by radioproline cytotoxicity assays and by immunoglobulin binding detected with SPA or antiglobulin against the battery of colonic and other neoplastic cell lines, as well as normal human lymphocytes, colonic adult and fetal normal epithelium in continuous culture; and b) susceptibility to inhibition upon pre-incubation with purified antigenic fractions. Normal colonic epithelial cell cultures will be established utilizing a combination of new isolation methods and application of proliferative stimulus growth factors, insulin, hydrocortisone, polyamines, and gastrin, as indicated in our previous work with colonic and urothelial cells. Colonic cell extracts solubilized 3M KCl extraction and/or a butanol extraction are fractionated by preparative isoelectric focusing, lectin affinity chromatography and two-dimensional polyacrylamide gel electrophoresis. Further colon cancer lines will be utilized to dissect factors responsible for organoid differentiation of neoplastic cells, utilizing the model of glandular formation on hollow fiber by some cultured cells and their clones. These studies may provide insight into humoral mediators which might be developed as chemotherapeutic agents to enhance organoid formation and possibly retard neoplastic proliferation of anaplastic tumors. These fundamental studies employing monospecific antibody reagents and purified cell components may afford insig (Text Truncated - Exceeds Capacity)